1. Field of the Invention
The present invention relates to a laser scanning unit and an image forming apparatus having the same. More particularly, the present invention relates to a laser scanning unit and an image forming apparatus having the same in which the interference caused by light that is removed during shaping and the inflow of the removed light into an optical system are substantially prevented and the productivity of the optical components is improved.
2. Description of the Related Art
Generally, a laser scanning unit (LSU) is employed in laser printers, digital photocopiers, bar code readers, and facsimiles, and forms a latent image by scanning with a beam deflector and sub-scanning through rotation of a photoreceptor.
FIG. 1 illustrates main elements of a conventional LSU. Referring to FIG. 1, in the conventional LSU, divergent laser light emitted from a laser light source (not shown) is collimated by a collimating lens (not shown). A portion of the collimated light passes through a throttle member 30 including an aperture 32 to pass a portion of a light beam, and thus the light beam forms an optimal light spot on a photoconductor (not shown). The portion of the light beam not transmitted by the throttle member 30 is reflected by a tapered surface 34 of the throttle member 30 and proceeds away from the optical axis LO. The tapered surface 34 is inclined with respect to the cross section of the light beam and reflects incident light away from the optical axis LO so that reflected light C does not return to the collimating lens. Thus, a decrease of light power and image quality due to light concentration on a laser light source or an unnecessary image formed on a photoconductor is prevented.
The throttle member 30 including the tapered surface 34 may be produced in large quantities using a press process. However, when a tapered edge is made using a press process, stress concentrates locally in a material disposed between an upper die and a lower die, and thus inferior products may be produced since plasticity flow is blocked, and the edge portions may be easily cut or thin.
Accordingly, a need exists for an improved light source for a laser scanning unit in which light removed during beam shaping is not reflected onto optical components.